Amine organoborane complex polymerization initiators and polymerizable compositions

ABSTRACT

The invention is a method of polymerization comprising contacting the components of the polymerizable composition of  
     a) an organoborane/amine complex wherein the amine is selected from the group of amines having an amidine structural component; aliphatic heterocycles having at least one nitrogen in the heterocyclic ring; an alicyclic compound having bound to the ring a substituent having an amine moiety; primary amines which in addition to a primary amine have one or more hydrogen bond accepting groups of an ether, polyether, thioether or halogen wherein there is an alkylene chain of at least two carbon atoms between the primary amine and the hydrogen bond accepting group; and conjugated imines;  
     b) one or more of monomers, oligomers or polymers having olefinic unsaturation; and  
     c) in the presence of an effective amount of a compound which causes the complex to disassociate or at a temperature at which causes the complex to disassociate.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation-in-part (CIP) of copendingapplication Ser. No. 09/466,321, filed Dec. 17, 1999.

BACKGROUND OF THE INVENTION

[0002] This invention relates to organoborane amine complexes that areuseful as free radical polymerization initiators. In another embodiment,this invention relates to polymerizable compositions comprisingcompounds containing moieties capable of free radical polymerization andorganoborane amine complex initiators of the invention. In yet anotherembodiment the invention relates to adhesive, sealant, coating and inkcompositions containing organoborane amine complexes and compoundscontaining moieties capable of free radical polymerization.

[0003] In many practical situations in which compounds are subjected topolymerization or where adhesives are used, it is desirable to havepolymerizable compositions and adhesive compositions which can cure ondemand. Cure on demand means that the polymerization can be initiatedwhen desired. A significant problem with cure on demand compositions isthe stability of the compositions. Many such compositions will begincuring at, or near, ambient temperature or will partially cure atambient temperature resulting in an increased viscosity causingdifficulties in handling and reduced functionality of the polymerizablecomposition or adhesive composition.

[0004] Low surface energy olefins such as polyethylene, polypropyleneand polytetrafluroethylene have a variety of attractive properties in avariety of uses, such as for toys, automobile parts, furnitureapplications and the like. Because of the low surface energy of theseplastic materials, it is very difficult to find adhesive compositionswhich bond to these materials. The commercially available adhesiveswhich are used for these plastics require time consuming or extensivepretreatment of the surface before the adhesive will bond to thesurface. Such pretreatments include corona treatment, flame treatmentand the like. The requirement for extensive pretreatment of the surfaceresults in significant limitations to the designers of automobilecomponents, toys, furniture and the like. What is needed is adhesivecompositions which are capable of bonding to low surface energysubstrates, and bonding low surface energy substrates to othersubstrates, without the need for extensive or costly pretreatment.

[0005] Mottus et al., U.S. Pat. No. 3,275,611 discloses a process forpolymerizing olefinic compounds with a catalyst comprising anorganoborane compound, a peroxygen compound and an amine (incorporatedherein by reference). It is disclosed that the organoborane compound andamine may be added to the reaction mixture separately or as a preformedcomplex, and that the complex is preferred. The presence of the amine inthe complex reduces the pyrophoricity of the organoborane in air. Amongthe amine complexing agents disclosed are pyridine, aniline, toluidine,dimethylbenzylamine, and nicotine. Many of the complexes disclosed inMottus are pyrophoric at all amine to boron atom ratios. In addition,many of the amine complexes do not display significant adhesiveproperties when applied to low surface energy substrates.

[0006] A series of patents issued to Skoultchi (U.S. Pat. Nos.5,106,928, 5,143,884, 5,286,821, 5,310,835 and 5,376,746) (allincorporated herein by reference) disclose a two-part initiator systemthat is reportedly useful in acrylic adhesive compositions. The firstpart of the two-part system includes a stable organoborane-amine complexand the second part includes a destabilizer or activator such as anorganic acid or an aldehyde. The organoborane compound of the complexhas three ligands which can be selected from C_(1/10) alkyl groups orphenyl groups. Useful amines disclosed include octylamine, 1,6diaminohexane, diethylamine, dibutylamine, diethylenetriamine,dipropylenediamine, 1,3 propylene diamine, and 1,2 propylene diamine.The adhesive compositions are disclosed to be useful in structural andsemi-structural adhesive applications, such as speaker magnets, metal tometal bonding, automotive glass to metal bonding, glass to glassbonding, circuit board component bonding, bonding select plastics tometal, glass to wood, etc. and for electric motor magnets.

[0007] Zharov et al. discloses in a series of U.S. patents (U.S. Pat.No. 5,539,070; U.S. Pat. No. 5,690,780; and U.S. Pat. No. 5,691,065)(all incorporated herein by reference) polymerizable acryliccompositions which are particularly useful as adhesives whereinorganoborane amine complexes are used to initiate cure. Theorganoboranes used have three ligands attached to the borane atom whichare selected from C₁₋₁₀ alkyl groups and phenyl. The amine is an alkanolamine or a diamine where the first amine group can be a primary orsecondary amine and the second amine is a primary amine. It is disclosedthat these complexes are good for initiating polymerization of anadhesive which bonds to low surface energy substrates.

[0008] Pocius in a series of patents (U.S. Pat. No. 5,616,796; U.S. Pat.No. 5,6211,43; U.S. Pat. No. 5,681,910; U.S. Pat. No. 5,686,544; U.S.Pat. No. 5,718,977; and U.S. Pat. No. 5,795,657) (all incorporatedherein by reference) disclose amine organoborane complexes with avariety of amines such as polyoxyalkylene polyamines and polyamineswhich are the reaction product of diprimary amines and compound havingat least two groups which react with a primary amine.

[0009] Many of the complexes disclosed in the Zharov, Skoultchi andPocius patents are not stable in compositions containing olefinicunsaturation at, or near, ambient temperatures and thus the complexesdisassociate and induce polymerization at, or near, ambient temperaturewith time. This instability at, or near, ambient temperature can resultin polymerization before desired and can result in compositions whichare unsuitable for the desired use.

[0010] Therefore, there is a need for initiator systems for free radicalpolymerization which are safe to handle, not pyrophoric, which can beused to form cure on demand polymer systems or can be used in adhesivesystems which cure on demand. What is further needed are adhesivesystems which are capable of bonding to low surface energy substrates,and initiator systems which facilitate such bonding. In addition to suchneeds, the complexes need to be thermally stable, that is do notdisassociate at, or near, ambient temperatures and thereby initiatepolymerization before desired. What are further needed are polymercompositions and adhesive systems which are thermally stable at, ornear, ambient temperatures and which will undergo polymerization whenthe user desires.

SUMMARY OF INVENTION

[0011] In one embodiment the invention is an amine organoborane complexwherein the organoborane is a trialkyl borane and the amine is selectedfrom the group of amines having an amidine structural component;aliphatic heterocycles having at least one nitrogen in the heterocyclicring wherein the heterocyclic compound may also contain one or morenitrogen atoms, oxygen atoms, sulfur atoms, or double bonds in theheterocycle; an alicyclic compound having bound to the ring asubstituent having an amine moiety wherein the compound may have asecond substituent which can contain one or more nitrogen, oxygen,sulfur or one or two double bonds; primary amines which in addition haveone or more hydrogen bond accepting groups wherein there are at leasttwo carbon atoms, preferably at least three carbon atoms, between theprimary amine and the hydrogen bond accepting group, such that due tointer- or intramolecular interactions within the complex the strength ofthe B—N bond is increased; and conjugated imines. Preferred hydrogenbond accepting groups include the following: primary amines, secondaryamines, tertiary amines, ethers, halogens, polyethers or polyamines.Heterocycle as used herein refers to a compound having one or morealiphatic cyclic rings of which one of the rings contains nitrogen. Theamidines or conjugated imines can be straight or branched chain orcyclic.

[0012] In another embodiment the invention comprises a polymerizablecomposition which comprises an amine organoborane complex of theinvention and one or more of monomers, oligomers or polymers havingolefinic unsaturation which are capable of polymerization by freeradical polymerization. This composition can undergo polymerization byexposing the composition to temperatures at which the organoborane aminecomplex undergoes disassociation. In another embodiment the invention isa polymerizable composition which further comprises an effective amountof a compound which causes the complex to disassociate (decomplexingagent), thereby freeing the borane to initiate polymerization of the oneor more monomers, oligomers or polymers having olefinic unsaturation.The compound which causes disassociation of the complex is kept separatefrom the complex until initiation of polymerization is desired. In yetanother embodiment the invention is a method of polymerizationcomprising a contacting of the components of the polymerizablecompositions under conditions that the one or more monomers, oligomersor polymers undergo polymerization. The polymerizable composition whichcontains the decomplexing agent can be cured at any desired temperature,such as at, or near, ambient temperature and below ambient temperature.

[0013] The polymerizable compositions of the invention can be used asadhesive, sealant, coating or ink compositions. In one embodiment two ormore substrates are bonded together by contacting the components of theadhesive composition of the invention, including the decomplexing agent,together under conditions such that polymerization is initiated;contacting the adhesive composition with the two or more substrates;positioning the two or more substrates such that the adhesivecomposition is located between the two or more substrates wherein theyare in contact with one another; and allowing the adhesive to cure so asto bond the two or more substrates together. The thermally curingcompositions of the invention can be used to bond two or more substratestogether by contacting the adhesive composition with the substrates suchthat the adhesive composition is located between the two or moresubstrates and exposing the adhesive composition to a temperature atwhich the complex disassociates and initiating the free radicalpolymerization of the monomer, oligomers, polymers or a mixture thereof.

[0014] The complexes of the invention are safe to handle, notpyrophoric, are stable at, or near, ambient temperature and thereforewill not initiate polymerization at, or near, ambient temperature in theabsence of an initiator that causes the complex to disassociate. Thepolymeric compositions of the invention are stable at, or near, ambienttemperature and can be cured upon demand by contacting the complex withthe compounds which cause disassociation of the complex, oralternatively by heating the polymeric compositions above the thermaldisassociation temperature of the complex. Furthermore, the adhesive,sealant, coating and ink compositions of the invention can form goodbonds to low surface energy substrates without the need for primers orsurface treatment.

DETAILED DESCRIPTION OF THE INVENTION

[0015] The organoborane used in the complex is a trialkyl borane or analkyl cycloalkyl borane. Preferably such borane corresponds to Formula1:

BR²)₃  Formula 1

[0016] wherein B represents Boron; and R² is separately in eachoccurrence a C₁₋₁₀ alkyl C₃₋₁₀ cycloalkyl, or two or more of R² maycombine to form a cycloaliphatic ring. Preferably R² is C₁₋₄ alkyl, evenmore preferably C₂₋₄ alkyl, and most preferably C₃₋₄ alkyl. Amongpreferred organoboranes are tri-ethyl borane, tri-isopropyl borane andtri-n-butylborane. To prepare thermally stable polymerizablecompositions, thermally stable complexes which do not disassociate, ator near, ambient temperature are needed. The key to preparation of suchcomplexes, is the selection of the amine. The desirability of the use ofa given amine in an amine/organoborane complex can be calculated fromthe energy difference between the Lewis acid-base complex and the sum ofenergies of the isolated Lewis acid (organoborane) and base (amine)known as binding energy. The higher the binding energy the more stablethe complex.

Binding Energy=(Complex Energy−(Energy of Lewis Acid+Energy of Lewisbase))

[0017] Such binding energies can be calculated using theoreticalab-initio methods such as the Hartree Fock method and the 3-21G basisset. These computational methods are available commercially employingcommercial software and hardware such as SPARTAN and GAUSSIAN 98programs with a Silicon Graphics workstation. Amines havingamine/organoborane binding energies of ten kilocalories per mol orgreater are preferred, amines having a binding energy of 15 kilocaloriesper mol or greater are more preferred and even more preferred are amineswith a binding 20 kilocalories per mol or greater. In the embodimentwhere polymerization of the compositions of the invention is initiatedby use of a decomplexing agent the binding energy of the amine to theorganoborane is preferably about 50 kcal/mole or less and mostpreferably about 30 kcal/mole or less. In the embodiment wherepolymerization of the compositions of the invention is initiated by useof heat the binding energy of the amine is preferably about 100kcal/mole or less, more preferably about 80 kcal/mole or less and mostpreferably about 50 kcal/mole or less.

[0018] In one embodiment, the amine comprises a compound having aprimary amine and one or more hydrogen bond accepting groups, whereinthere are at least two carbon atoms, preferably at least about three,between the primary amine and hydrogen bond accepting groups. Preferablyan alkylene moiety is located between the primary amine and the hydrogenaccepting group. Hydrogen bond accepting group means herein a functionalgroup that through either inter- or intramolecular interaction with ahydrogen of the borane-complexing amine increases the electron densityof the nitrogen of the amine group complexing with the borane. Preferredhydrogen bond accepting groups include primary amines, secondary amines,tertiary amines, ethers, halogen, polyethers, thioethers, andpolyamines. More preferred hydrogen accepting groups are ethers,polyethers, thioethers and halogens. In a preferred embodiment, theamine corresponds to Formula 2:

NH₂ (CH₂_(b)C(R¹)₂_(a)—X  Formula 2

[0019] wherein:

[0020] R¹ is separately in each occurrence hydrogen a C₁₋₁₀ alkyl, C₃₋₁₀cycloalkyl;

[0021] X is hydrogen bond accepting moiety; a is an integer of about 1to about 10; and b is separately in each occurrence an integer of about0 to about 1, and the sum of a and b is from about 2 to about 10.Preferably R¹ is hydrogen or methyl. Preferably X is separately in eachoccurrence a hydrogen accepting moiety with the proviso that when thehydrogen accepting moiety is an amine it is a tertiary or a secondaryamine. More preferably X is separately in each occurrence —N(R⁸)_(e),—OR¹⁰, SR¹⁰ or a halogen wherein R⁸ is separately in each occurrenceC₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl or —(C(R¹)₂)_(d)—W; R¹⁰ is separately ineach occurrence, C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl, or —(C(R¹)₂)_(d)—W; ande is 0, 1, or 2. More preferably X is SR¹⁰, —OR¹⁰ or halogen. Mostpreferably X is SR¹⁰ or OR¹⁰. Preferably, R⁸ and R¹⁰ are C₁₋₄ alkyl or—(C(R¹)₂)_(d)—W, more preferably C₁₋₄ alkyl and most preferably methyl.W is separately in each occurrence hydrogen or C₁₋₁₀ alkyl or X and morepreferably hydrogen or C₁₋₄ alkyl. Preferably, a is about 1 or greaterand more preferably 2 or greater. Preferably a is about 6 or less, andmost preferably about 4 or less. Preferably, b is about 1. Preferably,the sum of a and b is an integer about 2 or greater and most preferablyabout 3 or greater. Preferably the sum of a and b are about 6 or lessand more preferably about 4 or less. Preferably d is separately in eachoccurrence an integer of about 1 to about 4, more preferably about 2 toabout 4, and most preferably about 2 to about 3. Among preferred aminescorresponding to Formula 2 are dimethylaminopropyl amine, methoxypropylamine, dimethylaminoethylamine, dimethylaminobutylamine, methoxybutylamine, methoxyethyl amine, ethoxypropylamine, propoxypropylamine, amineterminated polyalkylene ethers (such as trimethylolpropanetris(poly(propyleneglycol), amine terminated)ether), andaminopropylpropanediamine.

[0022] In one embodiment the preferred amine complex corresponds toFormula 3:

(R²₃B←NH₂(CH₂_(b)C(R¹)₂_(a)—X  Formula 3

[0023] wherein R¹, R², X, a and b are as defined hereinbefore.

[0024] In another embodiment the amine is an aliphatic heterocyclehaving at least one nitrogen in the heterocycle. The heterocycliccompound may also contain one or more of nitrogen, oxygen, sulfur ordouble bonds. In addition, the heterocycle may comprise multiple ringswherein at least one of the rings has a nitrogen in the ring. Preferablythe aliphatic heterocylic amine corresponds to Formula 4:

[0025] wherein:

[0026] R³ is separately in each occurrence hydrogen, a C₁₋₁₀ alkyl C₃₋₁₀cycloalkyl or forms a double bond with a R³ or R⁴ on an adjacent atom;

[0027] Z is separately in each occurrence oxygen, sulfur or NR⁴ whereinR⁴ is hydrogen, C₁₋₁₀ alkyl, or C₆₋₁₀ aryl or alkaryl;

[0028] x is separately in each occurrence an integer of about 1 to about10, with the proviso that the total of all occurrences of x should befrom about 2 to about 10; and

[0029] y is separately in each occurrence 0 or 1. Two or more of R³ andR⁴ may combine to form cyclic rings thereby forming a multicycliccompound. Preferably, R³ is separately in each occurrence hydrogen,methyl or forms a double bond with a R³ or R⁴ on an adjacent atom.Preferably Z is NR⁴. Preferably, R⁴ is hydrogen or C₁₋₄ alkyl, and morepreferably hydrogen or methyl. Preferably x is from about 1 to about 5and the total of all the occurrences of x is about 3 to about 5.Preferred compounds corresponding to Formula 4 include morpholine,piperidine, pyrolidine, piperazine, 1,3,3 trimethyl 6-azabicyclo[3,2,1]octane, thiazolidine, homopiperazine, aziridine,1,4-diazabicylo[2.2.2]octane (DABCO), 1-amino-4-methylpiperazine,3-pyrroline, aminopropylmorpholine, and the like. Complexes containingaliphatic heterocyclic amines preferably correspond to

[0030] Formula 5:

[0031] wherein R², R³, Z, x and y are as defined hereinbefore.

[0032] In yet another embodiment, the amine which is complexed with theorganoborane is an amidine. Any compound with amidine structure whereinthe amidine has sufficient binding energy as described hereinbefore withthe organoborane, may be used. Preferable amidine compounds correspondto Formula 6:

[0033] wherein:

[0034] R⁵ and R⁶ and are separately in each occurrence hydrogen, a C₁₋₁₀alkyl, C₃₋₁₀ cycloalkyl or N(R⁴)₂; two or more of R⁵, R⁶, and R⁷ maycombine in any combination to form a ring structure, which may have oneor more rings. Preferably R⁵ and R⁶ are separately in each occurrencehydrogen, C₁₋₄ alkyl or C₅₋₆ cycloalkyl or N(R⁴)₂. Preferably R⁷ isseparately in each occurrence hydrogen, C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl orpart of a ring structure. Most preferably R⁷ is H, methyl or part of acyclic ring. In the embodiment where two or more of R⁵, R⁶ and R⁷combine to form a ring structure the ring structure is preferably asingle or a double ring structure. Among preferred amidines are 1,8diazabicyclo[5,4]undec-7-ene; tetrahydropyrimidine;2-methyl-2-imidazoline; and 1,1,3,3-tetramethylguanidine, and the like.

[0035] The organoborane amidine complexes preferably correspond toFormula 7:

[0036] wherein R², R⁶ and R⁷ are as defined earlier.

[0037] In yet another embodiment, the amine which is complexed with theorganoborane is a conjugated imine. Any compound with a conjugated iminestructure, wherein the imine has sufficient binding energy as describedhereinbefore with the organoborane, may be used. The conjugated iminecan be a straight or branched chain imine or a cylic imine. Preferableimine compounds correspond to Formula 8:

NR⁷═CR⁹—(CR⁹═CR⁹_(c)Y  Formula 8

[0038] wherein Y is independently in each occurrence hydrogen, SR⁴,N(R⁴)₂, OR⁴, C(O)OR⁴, halogen or an alkylene group which forms a cyclicring with an R⁷ or R⁹. R⁴ is hydrogen, C₁₋₁₀ alkyl, C₆₋₁₀ aryl or C₆₋₁₀alkaryl. Preferably R⁴ is hydrogen or methyl. R⁷ is as describedpreviously. R⁹ is independently in each occurrence hydrogen, Y, C₁₋₁₀alkyl, C₃₋₁₀ cycloalkyl-, (C(R⁹)₂—(CR⁹═CR⁹)_(c)—Y or two or more of R⁹can combine to form a ring structure provided the ring structure isconjugated with respect to the double bond of the imine nitrogen; and cis an integer of from about 1 to about 10. Preferably, R⁹ is hydrogen ormethyl. Y is preferably SR⁴, N(R⁴)₂, or OR⁴, or an alkylene group whichforms a cyclic ring with R⁷ or R⁹. Y is more preferably N(R⁴)₂ or analkylene group which forms a cyclic ring with R⁷ or R⁹. Preferably, c isan integer of from about 1 to about 5, and most preferably about 1.Among preferred conjugated imines useful in this invention are4-dimethylaminopyridine; 2,3-bis(dimethylamino)cyclopropeneimine;3-(dimethylamine)acroleinimine; 3-(dimethylamino)methacroleinimine, andthe like.

[0039] Among preferred cyclic imines are those corresponding to thefollowing structures

[0040] The complexes with the conjugated imines preferably correspond toFormula 9:

(R²₃B←NR⁷═CR⁹—(CR⁹═CR⁹_(c)Y  Formula 9

[0041] wherein R², R⁷,R⁹, c and Y are as defined hereinbefore.

[0042] In another embodiment the amine can be an alicyclic compoundhaving bound to the alicyclic ring a substituent containing an aminemoiety. The amine containing alicyclic compound may have a secondsubstituent which contains one or more nitrogen, oxygen or sulfur atomsor a double bond. The alicyclic ring can contain one or two doublebonds. The alicyclic compound may be a single or multiple ringstructure. Preferably the amine on the first substituent is primary orsecondary. Preferably the alicyclic ring is a 5 or 6 membered ring.Preferably functional groups on the second substituent are amines,ethers, thioethers, halogens. Preferably the amines are secondary ortertiary. In a preferred embodiment the alicyclic compound with an aminecontaining substituent corresponds to Formula 10

[0043] wherein R³, X, and x are as described hereinbefore. Included inamine substituted alicyclic compounds is isophorone diamine. B is aminomethyl cyclohexane in all its isomeric forms.

[0044] Complexes using amine substituted alicyclic compounds correspondto Formula 11

[0045] wherein R², R³, X, a, b and x are as defined hereinbefore.

[0046] The molar ratio of amine compound to borane compound in thecomplex is relatively important. In some complexes if the molar ratio ofamine compound to organoborane compound is too low, the complex ispyrophoric. Preferably the molar ratio of amine compound to organoboranecompound is from about 1.0:1.0 to about 3.0:1.0. Below the ratio ofabout 1.0:1.0 there may be problems with polymerization, stability ofthe complex and for adhesive uses, adhesion. Greater than about a3.0:1.0 ratio may be used although there is no benefit from using aratio greater than about 3.0:1.0. If too much amine is present, this maynegatively impact the stability of the adhesive or polymer compositions.Preferably the molar ratio of amine compound to organoborane compound isfrom about 2.0:1.0 to about 1.0:1.0.

[0047] Polymerizable compounds which may be used in the polymerizationcompositions of the invention include any monomers, oligomers, polymersor mixtures thereof which contain olefinic unsaturation which canpolymerize by free radical polymerization. Such compounds are well knownto those skilled in the art. Mottus, U.S. Pat. No. 3,275,611, provides adescription of such compounds at column 2, line 46 to column 4, line 16,incorporated herein by reference. Among preferred classes of compoundscontaining olefinic unsaturation are monomers, oligomers, polymers andmixtures thereof derived from the acrylates and methacrylates;olefinically unsaturated hydrocarbons, for example ethylene, propylene,butylene, isobutylene, 1-octene, 1-dodecene, 1-heptadecene, 1-eicoseneand the like; vinyl compounds such as styrene, vinyl pyridine,5-methyl-2 vinylpyridine, vinyl napthylene, alpha methylstyrene; vinyland vinylidiene halides; acrylonitrile and methacrylonitrile; vinylacetate and vinyl propionate; vinyl oxyethanol; vinyl trimethylacetate;vinyl hexonate; vinyl laurate; vinyl chloroacetate; vinyl stearate;methyl vinyl ketone; vinyl isobutyl ether; vinyl ethyl ether; compoundsthat have a plurality of ethylenic bonds such as those having conjugateddouble bonds such as butadiene, 2 chlorobutadiene, isoprene; and thelike. Examples of preferable acrylates and methacrylates are disclosedin Skoultchi, U.S. Pat. No. 5,286,821 at column 3, lines 50 to column 6,line 12, incorporated herein by reference and Pocius, U.S. Pat. No.5,681,910 at column 9, line 28 to column 12, line 25, incorporatedherein by reference. More preferred olefinic compounds comprise methylacrylate, methylmethacrylate, butylmethacrylate, tertbutylmethacrylate,2-ethylhexyacrylate, 2-ethylhexylmethacrylate, ethylacrylate,isobornylmethacrylate, isobornylacrylate, hydroxyethylmethacrylate,glycidylmethacrylate, tetrahydrofurfuryl methacrylate, acrylamide,n-methylacrylamide, and other similar acrylate containing monomers. Alsouseful are the class of acrylate tipped polyurethane prepolymersavailable commercially from several sources, and prepared by reacting anisocyanate reactive acrylate monomer, oligomer or polymer, such as ahydroxy acrylate, with an isocyanate functional prepolymer.

[0048] In the embodiment where the composition is used as an adhesive,acrylate and/or methacrylate based compounds are preferably used. Themost preferred acrylate and methacrylate compounds includemethylmethacrylate, butylmethacrylate, 2-ethylhexylmethacrylate,isobornylmethacrylate, tetrahydrofurfuryl methacrylate, andcyclohexylmethylmethacrylate.

[0049] In some embodiments the polymerizable compositions of theinvention may further comprise an effective amount of a compound that isreactive with an amine so as to liberate the organoborane so as toinitiate polymerization (a decomplexing agent). The amine reactivecompound liberates organoborane by reacting with the amine, therebyremoving the organoborane from chemical attachment with the amine.Desirable amine reactive compounds are those materials that can readilyform reaction products with amines at or below and more preferably atroom temperature, about 20° C. to 22° C., so as to provide a compositionthat can be generally easily used and cured under ambient conditions.General classes of such compounds include acids, aldehydes, isocyanates,acid chlorides, sulphonyl chlorides, mixtures thereof and the like.Preferred amine reactive compounds are acids. Both Bronstead and Lewisacids may be used. Pocius, U.S. Pat. No. 5,718,977 describes thepreferred acid compounds at column 9, line 1 to 15 incorporated hereinby reference. The most preferred acids are acrylic acid and methacrylicacid.

[0050] Preferably the amount of polymerizable compounds in thepolymerizable compositions or adhesive is about 20 percent by weight orgreater based on the weight of the total composition, more preferablyabout 30 percent by weight or greater and most preferably about 40percent by weight or greater. Preferably the amount of polymerizablecompounds is about 95 percent by weight or less, preferably about 90percent by weight or less and most preferably about 85 percent by weightor less. The amount of complex used in the composition can be any amountsufficient to initiate polymerization once the complex has disassociatedat the desired speed of polymerization. At higher concentration oforganoborane, the speed of polymerization is higher. Preferably theamount of organoborane complex is about 0.2 percent by weight or greaterbased on the weight of the total composition, preferably about 1.0percent by weight or greater and most preferably about 2 percent byweight or greater. Preferably the amount of organoborane complex presentis about 8 percent by weight or less based on the total weight ofcomposition, preferably about 6 percent by weight or less and mostpreferably about 4 percent by weight or less. In those embodiments wherea decomplexing agent is used, the amount of decomplexing agent(initiator) is that amount which is sufficient to initiatedisassociation of the organoborane-amine complex thereby causing theorganoborane to initiate polymerization of the olefinically unsaturatedcompound. Preferably the amount of decomplexing agent is about 1 percentby weight or greater based on the weight of the total composition, morepreferably about 1.5 percent by weight or greater and most preferablyabout 2.0 percent by weight or greater. Preferably the amount ofdecomplexing agent is about 8 percent by weight or less based on theweight of the total composition, more preferably about 6 percent byweight or less and most preferably about 4 percent by weight or less.

[0051] The organoborane amine complex may be readily prepared usingknown techniques. Typically, the amine is combined with the organoboranein an inert atmosphere with slow stirring. An exotherm is often observedand cooling of the mixture is, therefore, recommended. If theingredients have a high vapor pressure, it is desirable to keep thereaction temperature below about 70° C. to 80° C. Once the materials arewell mixed the complex is permitted to cool to room temperature. Nospecial storage conditions are required although it is preferred thatthe complex be kept in a capped vessel under an inert atmosphere, in acool, dark location. Advantageously, the complexes of the invention canbe prepared in the absence of organic solvents that would later have tobe removed, although they could be prepared in solvent, if so desired.Solvents used in the preparation of the complexes should, preferably, beones that do not coordinate the amine, preferable solvents are forexample, tetrahydrofuran or diethylether, or low molecular weightalkanes such as hexane or heptane.

[0052] The complexes and compositions of the invention are air stable.By “air stable” it is meant that when the complexes are stored in acapped vessel at room temperature (about 20° C. to 22° C.) and underotherwise ambient conditions (i.e., not under a vacuum and not in aninert atmosphere), the complexes remain useful as polymerizationinitiators for at least about two weeks, although the complexes may bereadily stored under these conditions for many months.

[0053] By “air stable” it is also meant that the complexes are notpyrophoric. (When a few drops of the complex are placed on a paper towelunder ambient conditions, the paper towel does not ignite, char orsmoke.) The air stability of the complex is enhanced when the complex isa crystalline material. However, the complexes of the invention are airstable for at least six months even when they are liquids. Liquidcomplexes are easier to handle and mix than are crystalline complexes.

[0054] The polymerizable compositions of the invention can be either oneor two-part compositions depending upon the mechanism used to initiatepolymerizations. In one embodiment the compositions are two-partcompositions in which one-part contains the complexes of the inventionand the other part contains the decomplexing agent (initiator).Polymerization is initiated by contacting the two-parts of thecomposition. An advantage of this process is that polymerization can beinitiated at, or even below, ambient temperatures. In this embodimentheat may be applied to the polymerizable composition to speed upinitiation or polymerization. In another embodiment the polymerizationcomposition may be initiated by heating the composition. In thisembodiment no decomplexing agent (initiator) is needed. Whenpolymerization is initiated by heating the composition can be either aone-part or a two-part composition. The primary reason to use a two-partcomposition is to keep apart components of the composition which may beunstable in the presence of one another.

[0055] In the embodiment where heat is used to initiate the cure of thecomposition, the composition is exposed to a heat source which heats thecomposition to a temperature at or above the temperature at which thecomplex used in the composition decomposes to release the organoboranewhich then initiates free radical polymerization. Generally thecomposition is heated to a temperature which is less than thetemperature at which the polymer formed undergoes degradation. Thetemperature at which the complex undergoes disassociation is related tothe binding energy of the complex. At higher binding energies of thecomplex higher temperatures are required to initiate polymerization. Inthe embodiment where the polymerization is initiated thermally thetemperature at which the composition is heated to initiatepolymerization is dictated by the binding energy of the complex.Generally the temperature used to initiate the polymerization bydecomplexing the complex is about 30° C. or greater and preferably about50° C. or greater. Preferably the temperature at which thermallyinitiated polymerization is initiated is about 120° C. or less and morepreferably about 100° C. or less. Any heat source which heats thecomposition to the desired temperature can be used provided the heatsource does not negatively impact the components of the composition orits function. In this manner the composition may be contacted with thesubstrates either before or after the composition is exposed to heat. Ifthe composition is heated prior to contact with the substrates, thecomposition should be contacted with the substrates before thecomposition has polymerized to the point at which the composition is nolonger able to adhere to the substrates, this is usually the upper limiton the open time as defined hereinafter. It may be necessary in thethermally initiated reaction to control the oxygen content such thatthere is adequate oxygen to create favorable conditions for radicalformation but not so much as to inhibit the polymerization.

[0056] The two-part polymerizable compositions or adhesive compositionsof the invention are uniquely suited for use with conventional,commercially available dispensing equipment for two-part adhesives. Oncethe two-parts have been combined, the composition should be usedquickly, as the useful pot life (or open time) may be short dependingupon the monomer mix, the amount of complex, and the temperature atwhich the bonding is to be performed. The adhesive composition isapplied to one or both substrates and then the substrates are joinedtogether with pressure to force excess composition out of the bond line.This also has the advantage of displacing composition that has beenexposed to air and that may have begun to react. In general, the bondsshould be made shortly after the composition has been applied,preferably within about 10 minutes. The typical bond line thickness isabout 0.005 inches (0.13 mm) to about 0.03 inches (0.76 mm). The bondingprocess can easily be carried out at room temperature and to improve thedegree of polymerization it is desirable to keep the temperature belowabout 40° C., preferably below about 30° C., and most preferably belowabout 25° C.

[0057] The bonds will cure to a reasonable green strength to permithandling of the bonded components within about 2 to 3 hours. Fullstrength will be reached in about 24 hours under ambient conditions;post-curing with heat (typically about 80° C.) may be used if desired.

[0058] When bonding fluoroplastics, it is advantageous to cool theinitiator containing part of the two-part composition to about 0° C. toabout 5° C. before adding the organoborane amine complex. The bondshould be made as soon after the composition has been applied aspractical; performing the bonding operation at less than about roomtemperature is also helpful.

[0059] The compositions may further comprise a variety of optionaladditives. One particularly useful additive is a thickener such asmedium to high (about 10,000 to about 1,000,000) molecular weightpolymethyl methacrylate which may be incorporated in an amount of about10 to about 60 weight percent, based on the total weight of thecomposition. Thickeners may be employed to increase the viscosity of thecomposition to facilitate application of the composition.

[0060] Another particularly useful additive is an elastomeric material.The materials can improve the fracture toughness of compositions madetherewith which can be beneficial when, for example, bonding stiff, highyield strength materials such as metal substrates that do notmechanically absorb energy as easily as other materials, such asflexible polymeric substrates. Such additives can be incorporated in anamount of about 5 percent to about 35 percent by weight, based on thetotal weight of the composition. Useful elastomeric modifiers includechlorinated or chlorosulphonated polyethylenes such as HYPALON 30(commercially available from E. I. Dupont de Nemours & Co., Wilmington,Del.) and block copolymers of styrene and conjugated dienes(commercially available from Dexco Polymers under the Trademark VECTOR,and Firestone under the Trademark STEREON). Also useful, and even morepreferred, are certain graft copolymer resins such as particles thatcomprise rubber or rubber-like cores or networks that are surrounded byrelatively hard shells, these materials often being referred to as“core-shell” polymers. Most preferred are theacrylonitrile-butadiene-styrene graft copolymers available from Rohm andHaas. In addition to improving the fracture toughness of thecomposition, core-shell polymers can also impart enhanced spreading andflow properties to the uncured composition. These enhanced propertiesmay be manifested by a reduced tendency for the composition to leave anundesirable “string” upon dispensing from a syringe-type applicator, orsag or slump after having been applied to a vertical surface. Use ofmore than about 20 percent of a core-shell polymer additive is desirablefor achieving improved sag-slump resistance. Generally the amount oftoughening polymer used is that amount which gives the desired toughnessto the polymer or the adhesive prepared.

[0061] Another useful adjuvant is a cross-linking agent. Cross-linkingagents can be used to enhance the solvent resistance of the adhesivebond or polymer composition, although certain compositions of theinvention have good solvent resistance even in the absence of externallyadded cross-linking agents. Typically employed in an amount of about 0.2to about 10 weight percent based on the total weight of thecompositions, useful cross-linkers include the various diacrylatesreferred to above as possible acrylic modifying monomers as well asother materials. Particular examples of suitable cross-linking agentsinclude ethylene glycol dimethacrylate, ethylene glycol diacrylate,triethyleneglycol dimethacrylate, diethylene glycol bismethacryloxycarbonate, polyethylene glycol diacrylate, tetraethylene glycoldimethacrylate, diglycerol diacrylate, diethylene glycol dimethacrylate,pentaerythritol triacrylate, trimethylolpropane triglycidyl ether,trimethylolpropane tris(2-methyl-1-aziridinepropionate,trimethylolpropane trimethacrylate, acrylate tipped polyurethanecontaining prepolymers, polyether diacrylates and dimethacrylates.

[0062] Peroxides may be optionally included (typically in an amount ofabout 2 percent by weight or less, based on the total weight of thecomposition), for example, to adjust the speed at which the compositionspolymerize or to complete the polymerization.

[0063] Small amounts of inhibitors such as hydroquinone may be used, forexample, to prevent or reduce degradation of the olefinic monomersduring storage. Inhibitors may be added in an amount that does notmaterially reduce the rate of polymerization or the ultimate propertiesof an adhesive or other composition made therewith, typically about 10to about 10,000 ppm based on the weight of the polymerizable monomers.

[0064] Other possible additives include non-reactive colorants, fillers(e.g., carbon black), etc.

[0065] The various optional additives are employed in an amount thatdoes not significantly adversely affect the polymerization process orthe desired properties of compositions made therewith.

[0066] Polymerizable compositions according to the invention may be usedin wide variety of ways, including as sealants, coatings, primers, tomodify the surface of polymers, and injection molding resins. They mayalso be used as matrix resins in conjunction with glass and metal fibermats such as in resin transfer molding operations. They may further beused as encapsulants and potting compounds such as in the manufacture ofelectrical components, printed circuit boards and the like. Quitedesirably, they provide polymerizable adhesive compositions that canbond a diverse myriad of substrates, including polymers, wood, ceramics,concrete, glass and primed metals. Another desirable related applicationis their use in promoting adhesion of paints to low surface energysubstrates such as polyethylene, polypropylene,polyethyleneterephthalate and polytetrafluoroethylene, and theirco-polymers. In this embodiment the composition is coated onto thesurface of the substrate to modify the surface to enhance the adhesionof the final coating to the surface of the substrate.

[0067] The compositions of the invention can be used in coatingapplications. In such applications the composition may further comprisea carrier such as water or a solvent. The coating may further containadditives well known to those skilled in the art for use coatings suchas pigments to color the coating, inhibitors and UV stabilizers. Thecompositions may also be applied as powder coatings and may contain theadditives well known to those skilled in the art for use in powdercoatings.

[0068] The compositions of the invention can also be used to modify thesurface of a polymeric molded part, extruded film or contoured object.Compositions of the invention can also be used to change thefunctionality of a polymer particle by surface grafting of polymerchains on to the unmodified plastic substrate.

[0069] Alternatively, the complexes of the present invention can bedissolved in a variety of solvents including water or organic solventsthat provide a non acid containing environment and used as a primer. Inthis manner the complex containing solution is applied to the surfacethat is to be used for adhesion, surface modification, orpolymerization, and the solvent allowed to dry. The polymerizablemonomer is then brought into contact with the complex on the surface andallowed to react for the purpose of promoting adhesion, or surfacemodification, or for initiating radical polymerization.

[0070] Polymerizable compositions of the invention are especially usefulfor adhesively bonding low surface energy plastic or polymericsubstrates that historically have been very difficult to bond withoutusing complicated surface preparation techniques, priming, etc. By lowsurface energy substrates is meant materials that have a surface energyof about 45 mJ/m² or less, more preferably about 40 mJ/m² or less andmost preferably about 35 mJ/m² or less. Included among such materialsare polyethylene, polypropylene, acrylonitrile-butadiene-styrene,polyamides, syndiotactic polystyrene, olefin containing blockco-polymers, and fluorinated polymers such as polytetrafluoroethiene(TEFLON) which has a surface energy of less than about mJ/m². (Theexpression “surface energy” is often used synonymously with “criticalwetting tension” by others.) Other polymers of somewhat higher surfaceenergy that may be usefully bonded with the compositions of theinvention include polycarbonate, polymethlmethacrylate, andpolyvinylchloride.

[0071] The polymerizable compositions of the invention can be easilyused as two-part adhesive. The components of the polymerizablecompositions are blended as would normally be done when working withsuch materials. The decomplexing agent is usually included in this blendso as to separate it from the organoborane amine complex, thus providingone-part of the two-part composition. The organoborane amine complex ofthe polymerization initiator system provides the second part of thecomposition and is added to the first part shortly before it is desiredto use the composition. The complex may be added to the first partdirectly or it may be pre-dissolved in an appropriate carrier such asmethyl methacrylate.

[0072] It may be desirable to store the complexes apart from themonomers, oligomers or polymers to inhibit premature polymerization ofthe monomers, oligomers or polymers. The complexes of this inventionhave greatly enhanced stability when in the presence of monomers and inthe absence of a decomplexing agent, such as an acid, and thus can bestored with the polymerizable components of the composition. Complexesin which the complexing amine nitrogen atom to boron atom ratio isgreater than 1:1 may be sufficiently stable that they can be blendedwith polymerizable components in useful proportions. However, in suchsituations, the presence of additional non-polymerizing reactants (e.g.,the organoborane liberator) may result in other, undesirable affects.

[0073] For a two-part adhesive such as those of the invention to be mosteasily used in commercial and industrial environments, the ratio atwhich the two-parts are combined should be a convenient whole number.This facilitates application of the adhesive with conventional,commercially available dispensers. Such dispensers are shown in U.S.Pat. Nos. 4,538,920 and 5,082,147 (incorporated herein by reference) andare available from Conprotec, Inc. (Salem N.J.) under the trade nameMIXPAC. Typically, these dispensers use a pair of tubular receptaclesarranged side-by-side with each tube being intended to receive one ofthe two-parts of the adhesive. Two plungers, one for each tube, aresimultaneously advanced (e.g., manually or by a hand-actuated ratchetingmechanism) to evacuate the contents of the tubes into a common, hollow,elongated mixing chamber that may also contain a static mixer tofacilitate blending of the two-parts. The blended adhesive is extrudedfrom the mixing chamber onto a substrate. Once the tubes have beenemptied, they can be replaced with fresh tubes and the applicationprocess continued.

[0074] The ratio at which the two-parts of the adhesive are combined iscontrolled by the diameter of the tubes. (Each plunger is sized to bereceived within a tube of fixed diameter, and the plungers are advancedinto the tubes at the same speed.) A single dispenser is often intendedfor use with a variety of different two-part adhesives and the plungersare sized to deliver the two-parts of the adhesive at a convenient mixratio. Some common mix ratios are 1:1, 2:1, 4:1 and 10:1.

[0075] The part of the adhesive or polymerizable compositions of theinvention which contain the amine-organoborane complex preferablydisplays thermal stability at, or above, room temperature. Thermalstability as used herein means the amine organoborane complex does notdisassociate and initiate polymerization of the olefinic unsaturatedcompounds present in the composition. Thermal stability can be measuredby determining the temperature at which the viscosity of the compositionbegins to increase. Preferably the temperature at which the viscosity ofthe composition increases is greater than about 40° C., more preferablygreater than about 60° C. and most preferably greater than about 80° C.The increase in viscosity indicates that the amine borane complex isdisassociated and polymerization has been initiated. In the embodimentwherein the composition is used as an adhesive, the adhesive preferablydemonstrates a lap shear strength of about 100 p.s.i. (689 kPa) orgreater, more preferably about 250 p.s.i. (1724 kPa) or greater and morepreferably about 400 p.s.i. (2758 kPa) or greater according to thefollowing test procedure. The adhesive components are mixed and appliedto one or both substrates (1 in×4 in×{fraction (1/8)} in (25.4 mm×101.6mm×3.2 mm) polypropylene coupons). Adhesive thickness can be controlledby the addition of a few weight percent of glass beads between 0.005 to0.030 inches in diameter (0.13 mm to 0.76 mm). The coupons are mated toprovide 0.5 inch squared (161 mm²) to 1.0 inch squared (645 mm²)substrate overlap in a lap-shear testing configuration. The samples areheld in place with metal binder clips to provide constant force andfacilitate the elimination of air bubbles in the adhesive. The bondedsamples were usually cured for at least about 24 hours before beingmounted in a tensile testing apparatus fitted with a sample oven. Thesamples are evaluated at crosshead speeds of 0.05 (0.13 mm) and 0.5(12.7 mm) inches per minute for room temperature and 110° C. testingconditions, respectively. Maximum load (pounds) to break are recordedand maximum stress (psi) is calculated by dividing this load by theoverlap area (inches squared).

[0076] Preferably the open time of the adhesive is about 3 minutes orgreater, more preferably about 5 minutes or greater, and most preferablyabout 8 minutes or greater. Preferably the open time of the adhesive isabout 30 minutes or less, more preferably about 25 minutes or less, andmost preferably about 20 minutes or less. Open time as used herein isthe time between initiation of polymerization and the time at which theadhesive can no longer be applied and used as an adhesive. If the opentime is too long, poor bond strength is observed. If the open time istoo short, the composition polymerizes before a link up with thesubstrate can be achieved.

[0077] Preferably the polymeric compositions of the invention have asuitable viscosity to allow application. Preferably the compositionshave the viscosity of about 100 centipoise or greater, more preferableabout 1,000 centipoise or greater and most about 20,000 centipoise orgreater. Preferably the adhesive compositions have a viscosity of about150,000 centipoise or less, more preferably about 100,000 centipoise orless and most preferably about 50,000 centipoise or less.

[0078] Specific Embodiments

[0079] The following examples are included for illustrative purposesonly and are not intended to limit the scope of the claims. Unlessotherwise stated all parts and percentages are by weight.

[0080] Preparation of the Organoborane/Amine Complex

[0081] 50 cc of a 1M solution of organoborane, for example tributylborane (TBB) in ether solution (Aldrich), is added to a weighed roundbottom flask. The solution is purged with nitrogen. A weighed amount ofthe amine, for example pyrrolidine (4.97 g, 1:1.4 molar ratio of boronto amine), is added in small portions to the organoborane solution,maintaining the temperature below 40° C. with an external ice bath. Theamine is added to make a molar ratio of organoborane to amine of between1:1 to a 1:3. The solution is stirred for about 30 minutes and then thesolvent is removed on a rotary evaporator at less than 40° C. The weightof the flask and complex are periodically compared to the theoreticalweight to assure that the solvent is completely removed. The complex istested for pyrophoric reactivity by placing a drop on a paper towel andlooking for charring of the towel. Some pyrophoric complexes can be madeless or non-pyrophoric by adding additional amine (lowering theorganoborane:amine molar ratio).

[0082] Preparation of Adhesive Compositions

[0083] Two component (part) adhesives are produced as described below.One component includes the organoborane/amine complex (hardener) mixedwith an acrylic resin, described below, and an antioxidant. The othercomponent is the acrylic resin with an initiator, for example acrylicacid, that decomplexes the boron/amine complex when mixed into the othercomponent. The acrylic resin is a mixture of 250 g methylmethacrylate(MMA) and 80 g polymethylmethacrylate (PMMA, 350 K Mw). The MMA and PMMAare stirred or rotated overnight to mix the PMMA into the MMA. Theresulting acrylic resin has with a viscosity of about 25,000 centipoise(cP).

[0084] The first component (Part I) comprises 135 g acrylic resin, 6.6 gof a hardener, and 82.5 mg BHT (2,6-ditertbutyl-4-methyl phenol). Thesecond component comprises 135 g acrylic resin, 6.6 g acrylic acid (AA),13.5 g fillers (glass beads, polypropylene ground flakes, etc.) (<10%),and 13.5 g tougheners (Stereon 840A block copolymer) (<10%)). The twocomponents of the adhesive composition are formulated to allow for aratio of 1:1, 1:4, or 1:10 mixture of hardener:initiator, preferably1:1.

[0085] The adhesive may be mixed in the desired ratio in air, in a bag,or through a pressurized gun. The adhesive is applied to a polypropylenetest strip 1 inch (25.4 mm) wide with a {fraction (1/2)} inch (12.7 mm)overlap and is tested for adhesive strength as described previously.

[0086] Thermal stability testing is performed according to theprocedures provided below. The auto-initiation temperature is determinedfrom the point at which the viscosity starts to rise, indicating theonset of polymerization of the borane:amine containing resin withoutinitiator. Onset occurs due to thermal destabilization of theboron/amine complex. Viscosity is measured continuously by a Brookfieldviscometer (rotating cylinder at 50 rpm) as a function of a constanttemperature ramp (about 1° C./min). The temperature at which theviscosity begins to increase is noted and listed as the take offtemperature.

[0087] In another method the time it takes for the viscosity to reach100 kcPs at ambient temperature (or elevated temperature) is determinedby periodic measurement of the viscosity of a hardener and resin over aperiod of days. This is considered to be the useful lifetime of theresin.

[0088] Several complexes were prepared and tested in the composition asdescribed herein. Table 1 contains the results of the testing.

[0089] The following abbreviations are used in Table 1.

[0090] TBB is tri-n-butyl borane.

[0091] DMAPA is dimethylaminopropylamine.

[0092] TiBB is triisobutylborane.

[0093] DEBM is diethylmethoxyborane

[0094] DEBI is diethylisopropoxy borane

[0095] TOB is tri-n-octylborane

[0096] > means the substrate broke during measurement

[0097] Y means that paper ignited or charred when contacted with theborane:amine

[0098] N means that paper did not ignite, char, smoke, or discolor whencontacted by borane:amine.

[0099] Sl means that the paper showed slight evolution of smoke ordiscoloration, but not charring when contacted with borane:amine. TABLE1 Take- Lap Ex- Molar off Shear am- B: Pyro- Temp (on PP) ple BoraneAmine Amine phoric? (C) psi 1 TBB Hexane diamine 1:1 N 44 >444 2 TBBDMAPA 1:1.1 N 52 >900 3 TBB DMAPA 1:1.2 N 53 >655 4 TiBB DMAPA 1:1.25 N39 >604 5 TBB DMAPA 1:0.6 N 47 >929 6 TBB Tetramethyl 1:3 Y 46 192propane diamine 7 TPB DMAPA 1:1.1 N >100 0 8 TBB Aminopropyl 1:1.1 N50 >682 morpholine 9 TBB Cyclohexylamine 1:1.2 sl 20 >933 10 TBBAminopropanol 1:1.2 N 20 >624 11 TBB Morpholine 1:1.2 Y 20 >818 12 TBBEthanolamine 1:1.17 N 42 458 13 TBB Piperidine 1:1.5 N 52 >783 14 TBBPyrrolidine 1:1.4 N >100 679 15 DEBM DMAPA 1:1.25 N 68 36 16 DEBI DMAPA1:1.25 N 77 64 17 TBB Isophorone 1:1.36 N 46 >893 diamine 18 TBBMethoxypropyl 1:1.36 N 63 >640 amine 19 TBB a-Methyl 1:1.6 sl 25 451Benzylamine 20 TOB DMAPA 1:1.3 N >100 471 21 TBB Aminopropyl 1:1.2 N64 >559 propane diamine 22 TBB Aminoethoxy 1:1.3 N 25 >847 ethanol 23TOB Methoxypropyl 1:1.3 N 68 110 amine 24 TOB Aminopropanol 1:1.3 N 5379 25 TBB Morpholine 1:3 N 42 >878 26 TBB Aminopropanol 1:2 N 60 >419 27TOB Isophorone 1:1.3 N >100 0 diamine 28 TBB Diisopropyl 1:2 Y 50 0amine 29 TBB Cyclohexylamine 1:2 N 30 508 30 TBB Piperidine 1:2 N85 >775 31 TBB Aminoethoxy 1:2 N 50 276 ethanol 32 TBB Pyrrolidine 1:1.4N >100 >709 33 TiBB Pyrrolidine 1:1.4 N >100 303 34 TBB Piperazine 1:1.3N 20 >749 35 TBB Methyl 1:2 Y 20 0 pyrrolidinone 36 TBB Tetrahydro-1:1.3 N 20 0 thiophene 37 TBB Diethanol amine 1:2 Y 65 61 38 TBBTriethyl amine 1:2 Y 52 0 39 TBB Dibutylamine 1:1.3 N 50 39 40 TBBDipropylamine 1:1.3 Y 52 0 41 TBB Dioctylamine 1:1.3 N 58 192 42 TBBCyclopentyl 1:1.3 Y 25 >790 amine 43 TBB Cyclopentyl 1:2 N 25 >940 amine44 TiBB Isophorone 1:1.3 N 25 300 diamine 45 TOB Methoxypropyl 1:1.3 N50/83 amine 46 TBB 1,3,3 trimethyl 6- 1:1.3 N 25/ >426 azabicyclo[3,2,1] >100 octane 47 TBB Dabco 1:1.3 sl 25 >774 48 TBB Diamino1:1.3 Y NA maleonitrile 49 TBB Thiazolidine 1:1.3 Y 25 >725 50 TBBThiazolidine 1:2 N 25 186 51 TBB Urea 1:1.3 Y NA 52 TBB 1,8 Diazabicyclo[5, 1:1.3 N >100 >555 4] undec-7-ene 53 TBB 4-Dimethylamino 1:3 N57 >581 pyridine 54 TBB Proline methyl ester 1:1.3 N 0 55 TBB 4-Bromopiperidine 1:1.3 Y 0 56 TBB Acetaldehyde 1:1.3 sl 67 0 Ammonia Trimer 57TBB 1-Amino-4-Methyl 1:1.3 N 25 145 Piperazine 58 TBB Homopiperazine1:1.3 N 25 638 59 TBB 2- 1:3 sl 25 0 Dimethyl- aminopyridine 60 TBBPyridine 1:3 N 25 61 TBB Tetraaza 1:2 Y 0 adamantane 62 TBB Hexylamine1:1.3 N 45 >885 63 TBB Tetramethyl- 1:1.3 N 74 >616 guanidine 64 TBBTetrahydro- 1:1.3 N 75 >736 pyrimidine 65 TBB 2-Methyl 1:1.3 N 35 >10002-imidazoline 66 TBB 3-Pyrroline 1:1.3 N 25 247 67 TBBTrimethylolpropane 1:1.3 N 42 >620 tris[poly- (propylenegly- col), amineterminated]ether (avg mwt = 432) 68 TBB Trimethylolpropane 1:1.3 Y <25 0tris (2-methyl-1- aziridinepropionate

[0100] Binding Energies of Complexes

[0101] The organoborane/amine binding energies of several of thecomplexes are calculated using previously described computationalmethods. Comparison of results of amine/organoborane combinations listedin Table 1 with calculated binding energies in Table 2 reveal thatbinding energies less than about 10 kcal/mole are pyrophoric, and a highbinding energy is correlated with higher thermal performance.Furthermore the calculated binding energy is correlated with thetemperature at which the alkylborane-amine complex spontaneouslydisassociates. The disassociation temperature is easily determined bythe so called “take-off” temperature provided in Table 1 at which timethe polymerization proceeds in the absence of a de-complexing agent. Thedisassociation temperature may also be determined by differentialscanning calorimetry. When applying differential scanning calorimetry, asample of the complex is placed in a pan and the temperature of the panis raised. At the same time a reference sample, usually an empty pan, isheated at the exact same rate and the difference in temperature betweenthe sample and the reference is monitored and recorded using adifferential amplifier. When reaction of the complex is observed anexotherm can be observed implying a release of heat due to insertion ofoxygen into the alkyl-boron bond. No exotherm is observed when thisexperiment is performed under strictly inert conditions. TABLE 2 BindingLewis Energy (kcal/ Example Acid Amine mole) 2 TBB DMAPA cyclic¹ 20.4 2TBB DMAPA linear 15.9 25 TBB morpholine 12.8 32 TBB pyrrolidine 15.4 17TBB isophorone diamine cis 15.1 17 TBB isophorone diamine trans 15.3 18TBB methoxypropylamine cyclic¹ 20.1 18 TBB methoxypropylamine, linear15.4 21 TBB aminopropylpropanediamine 18.3 38 TBB triethylamine 0.0 47TBB Dabco 10.2 53 TBB 4-dimethylaminopyridine 16.2 60 TBB pyridine 8.7TBB dimethylaminoethylamine 18.8 TBB dimethylaminobutylamine 21.9 TBBpropylamine 15.8 TBB acetamidine 19.2 TBB guanidine 21.0 TBBcyclopropeneimine 17.0 TBB tetramethyldiaminocyclopropene 23 imine TBB3-N-methyl-3,4,5,6- 16.4 tetrahydropyrimidine TBB pyrazole 10.2 TBB3-aminopyrazole 13.1 TBB aziridine 18.0 TBB methylaziridine 14.9 TBBazetidine 17.9 TBB methylazetidine 12.2 TBB formaldimine 13.2 TBBbenzaldimine 11.5 TBB 3,4,5,6-tetrahydropyridine 12.2 TBB5,6-dihydropyridine 13.1 TBB cyclohexanone imine 12.8 TBB2-aminopropanal 15.8 TBB 1,4-dihydropyrrole 15.0 TBB N-Methyl- 16.4Tetrahydropyrimidine TBB 1-azabutadiene 13.8 TBB 4-N,N-dimethylamino-1-19.5 azabutadiene TBB 4-Methoxy-1-azabutadiene 16.2 TBB4-Chloro-1-azabutadiene 11.0 TBB 1-Azahexatriene 15.0

[0102] Among other compounds for which the binding energy is calculated,are those illustrated below with their calculated binding energiesadjacent.

What is claimed is:
 1. A method of polymerization comprising contacting the components of the polymerizable composition of a) an organoborane/amine complex wherein the organoborane is a trialkyl borane or an alkyl cycloalkyl borane and the amine is selected from the group of amines having an amidine structural component; aliphatic heterocycles having at least one nitrogen in the heterocyclic ring wherein the heterocyclic compound may also contain one or more nitrogen atoms, oxygen atoms, sulfur atoms, or double bonds in the heterocycle; an alicyclic compound having bound to the ring a substituent having an amine moiety wherein the alicyclic compound may have a second substituent which can contain one or more nitrogen, oxygen or sulfur atoms and/or one or two double bonds; primary amines which in addition to a primary amine have one or more hydrogen bond accepting groups of an ether, polyether, thioether or halogen wherein there is an alkylene chain of at least two carbon atoms between the primary amine and the hydrogen bond accepting group; and conjugated imines; and, b) one or more of monomers, oligomers or polymers having olefinic unsaturation which is capable of polymerization by free radical polymerization; c) an effective amount of a compound which causes the complex to disassociate freeing the borane to initiate polymerization of the one or more monomers, oligomers or polymers having olefinic unsaturation; wherein the compound which causes disassociation of the complex is kept separate from the complex until initiation of polymerization is desired under conditions such that the one or more monomers, oligomers, or polymers undergo polymerization.
 2. The method of claim 1 wherein the contacting occurs at, or near, ambient temperature.
 3. A method according to claim 2 wherein the complex of the organoborane and the primary amine corresponds to the formula (R²₃B←NH₂(CH₂_(b)C(R¹)₂_(a)—X; the organoborane heterocyclic amine complex corresponds to the formula

the organoborane amidine complex corresponds to the formula

the organoborane conjugated imine complex corresponds to the formula (R²₃B←NR⁷═CR⁹—(CR⁹═CR⁹_(c)Y; and the amine substituted alicyclic compound complex corresponds to the formula

wherein B is boron; R¹ is separately in each occurrence hydrogen, a C₁₋₁₀ alkyl or C₃₋₁₀ cycloalkyl; R² is separately in each occurrence a C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl or two or more of R² may combine to form a cycloaliphatic ring structure; R³ is separately in each occurrence hydrogen, a C₁₋₁₀ alkyl C₃₋₁₀ cycloalkyl or forms a double bond with a R³ or R⁴ on an adjacent atom; R⁴ is separately in each occurrence hydrogen, C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl, C₆₋₁₀ aryl or C₆₋₁₀ alkaryl; R⁵ and R⁶ are separately in each occurrence hydrogen, C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl, N(R⁴)₂ wherein R⁷ is separately in each occurrence hydrogen, C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl, or two or more of R⁵, R⁶ and R⁷ in any combination can combine to form a ring structure which can be a single ring or a multiple ring structure and the ring structure can include one or more of nitrogen, oxygen or unsaturation in the ring structure; R⁹ is independently in each occurrence hydrogen, C₁₋₁₀ alkyl or C₃₋₁₀ cycloalkyl, Y, —(C(R⁹)₂—(CR⁹═CR⁹)_(c)—Y or two or more of R⁹ can combine to form a ring structure, or one or more of R⁹ can form a ring structure with Y provided the ring structure is conjugated with respect to the double bond of the imine nitrogen; R¹⁰ is separately in each occurrence C₁₋₁₀ alkyl C₃₋₁₀ cycloalkyl or —(C(R¹)₂)_(d)—W; W is separately in each occurrence hydrogen, C₁₋₁₀ alkyl or X; X is OR¹⁰, SR¹⁰ or a halogen; Y is independently in each occurrence hydrogen, SR⁴, N(R⁴)₂, OR⁴, C(O)OR⁴, a halogen or an alkylene group which forms a cyclic ring with R⁷ or R⁹; Z is separately in each occurrence oxygen or —NR⁴; a is separately in each occurrence an integer of from about 1 to about 10; b is separately in each occurrence 0 or 1, with the proviso that the sum of a and b should be from about 2 to about 10; c is separately in each occurrence an integer of from about 1 to about 10; d is separately in each occurrence an integer of about 1 to about 4; x is separately in each occurrence an integer of about 1 to about 10, with the proviso that the total of all occurrences of x is from about 2 to about 10; and y is separately in each occurrence 0 or
 1. 4. A method according to claim 3 wherein: R¹ is separately in each occurrence hydrogen or methyl; R² is separately in each occurrence a C₂₋₄ alkyl group; R³ is separately in each occurrence hydrogen, methyl, or forms a double bond with an R³ or R⁴ on an adjacent atom; R⁴ is separately in each occurrence hydrogen, C₁₋₄ alkyl or; R⁵ and R⁶ are separately in each occurrence hydrogen, C₁₋₄ alkyl, C₅₋₆ cycloalkyl group, or N(R⁴)₂, R⁷ is separately in each occurrence hydrogen or methyl, with the proviso that two or more of R⁵, R⁶, and R⁷ can combine in any combination to form a single or multiple ring structure and can include one or more of nitrogen, oxygen or unsaturation in the ring; X is separately in each occurrence a SR¹⁰ or —OR¹⁰; Y is separately in each occurrence SR⁴, N(R⁴)₂ or OR⁴, an alkylene group which can also form a cyclic ring with R⁷ or R⁹; R⁹ is separately in each occurrence hydrogen, a C₁₋₁₀ alkyl, Y, —C(R⁹)₂—(CR⁹═CR⁹)_(c)—Y, or two or more of R⁹ can form a cyclic ring one or more of R⁹ or one or more of R⁹ can combine with Y to form a ring structure provided the ring structure is conjugated with respect to the double bond of the amine nitrogen; and a is an integer of about 2 to about 6; b is separately in each occurrence an integer of about 0 to about 1; c is separately in each occurrence an integer of from about 1 to about 5; and d is separately in each occurrence an integer of about 2 to about
 4. 5. A method according to claim 3 comprising an aliphatic heterocylic amine wherein the amine is a five or six membered heterocylic compound.
 6. A method according to claim 4 wherein the amine is a conjugated imine.
 7. A method according to claim 4 wherein the amine is a compound with an amidine structural component.
 8. A method according to claim 4 wherein the amine is an alicyclic compound having bound to the ring a substituent having an amine moiety wherein the alicyclic compound may have a second substitutent which can contain one or more nitrogen, oxygen or sulfur atoms and/or one or two double bonds.
 9. A polymerizable composition according to claim 8 wherein the alicyclic ring is a 5 or 6 membered ring.
 10. A method according to claim 4 wherein the decomplexing agent is an acid.
 11. A method according to claim 1 which comprises a) from about 0.2 to about 8 percent by weight of complex; b) from about 20 to about 95 percent by weight or less of monomers, oligomers or polymers; c) from about 1 to about 8 percent by weight of decomplexing agent; d) from about 10 to about 60 percent by weight of a thickener; and e) from about 5 to about 35 percent by weight of an elastomeric material.
 12. A process for polymerizing the composition comprising a) an organoborane/amine complex wherein the organoborane is a trialkyl borane or an alkyl cycloalkyl borane and the amine is selected from the group of amines having an amidine structural component; aliphatic heterocycles having at least one nitrogen in the heterocyclic ring wherein the heterocyclic compound may also contain one or more nitrogen atoms, oxygen atoms, sulfur atoms, or double bonds in the heterocycle; an alicyclic compound having bound to the ring a substituent having an amine moiety wherein the alicyclic compound may have a second substituent which can contain one or more nitrogen, oxygen or sulfur atoms and/or one or two double bonds; primary amines which in addition to a primary amine have one or more hydrogen bond accepting groups of an ether, polyether, thioether or halogen wherein there is an alkylene chain of at least two carbon atoms between the primary amine and the hydrogen bond accepting group; and conjugated imines; and, b) one or more of monomers, oligomers or polymers having olefinic unsaturation which is capable of polymerization by free radical polymerization; which process comprises heating the composition to a temperature at or above the temperature at which the organoborane-amine complex disassociates.
 13. The method of claim 12 wherein the composition is heated to a temperature of about 30° C. to about 120° C.
 14. The method of claim 13 wherein the composition is heated to a temperature of about 50° C. to about 100° C.
 15. A method according to claim 13 wherein the complex of the organoborane and the primary amine corresponds to the formula (R²₃B←NH₂(CH₂_(b)C(R¹)₂_(a)—X; the organoborane heterocyclic amine complex corresponds to the formula

the organoborane amidine complex corresponds to the formula

the organoborane conjugated imine complex corresponds to the formula (R²₃B←NR⁷═CR⁹—(CR⁹═CR⁹_(c)Y; and the amine substituted alicyclic compound complex corresponds to the formula

wherein B is boron; R¹ is separately in each occurrence hydrogen, a C₁₋₁₀ aklyl or C₃₋₁₀ cycloalkyl; R² is separately in each occurrence a C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl or two or more of R² may combine to form a cycloaliphatic ring structure; R³ is separately in each occurrence hydrogen, a C₁₋₁₀ alkyl C₃₋₁₀ cycloalkyl or forms a double bond with a R³ or R⁴ on an adjacent atom; R⁴ is separately in each occurrence hydrogen, C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl, C₆₋₁₀ aryl or C₆₋₁₀ alkaryl; R⁵ and R⁶ are separately in each occurrence hydrogen, C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl, N(R⁴)₂ wherein R⁷ is separately in each occurrence hydrogen, C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl, or two or more of R⁵, R⁶ and R⁷ in any combination can combine to form a ring structure which can be a single ring or a multiple ring structure and the ring structure can include one or more of nitrogen, oxygen or unsaturation in the ring structure; R⁹ is independently in each occurrence hydrogen, C₁₋₁₀ alkyl or C₃₋₁₀ cycloalkyl, Y, —(C(R⁹)₂—(CR⁹═CR⁹)_(c)—Y or two or more of R⁹ can combine to form a ring structure, or one or more of R⁹ can form a ring structure with Y provided the ring structure is conjugated with respect to the double bond of the imine nitrogen; R¹⁰ is separately in each occurrence C₁₋₁₀ alkyl, C₃₋₁₀ cycloalkyl or —(C(R¹)₂)_(d)—W; W is separately in each occurrence hydrogen, C₁₋₁₀ alkyl or X; X is OR¹⁰, SR¹⁰ or a halogen; Y is independently in each occurrence hydrogen, SR⁴, N(R⁴)₂, OR⁴, C(O)OR⁴, a halogen or an alkylene group which forms a cyclic ring with R⁷ or R⁹; Z is separately in each occurrence oxygen or —NR⁴; a is separately in each occurrence an integer of from about 1 to about 10; b is separately in each occurrence 0 or 1, with the proviso that the sum of a and b should be from about 2 to about 10; c is separately in each occurrence an integer of from about 1 to about 10; d is separately in each occurrence an integer of about 1 to about 4; x is separately in each occurrence an integer of about 1 to about 10, with the proviso that the total of all occurrences of x is from about 2 to about 10; and y is separately in each occurrence 0 or
 1. 16. A polymerizable composition according to claim 15 wherein: R¹ is separately in each occurrence hydrogen or methyl; R² is separately in each occurrence a C₂₋₄ alkyl group; R³ is separately in each occurrence hydrogen, methyl, or forms a double bond with an R³ or R⁴ on an adjacent atom; R⁴ is separately in each occurrence hydrogen, C₁₋₄ alkyl or; R⁵ and R⁶ are separately in each occurrence hydrogen, C₁₋₄ alkyl, C₅₋₆ cycloalkyl group, or N(R⁴)₂, R⁷ is separately in each occurrence hydrogen or methyl, with the proviso that two or more of R⁵, R⁶, and R⁷ can combine in any combination to form a single or multiple ring structure and can include one or more of nitrogen, oxygen or unsaturation in the ring; X is separately in each occurrence a SR¹⁰or —OR¹⁰; Y is separately in each occurrence SR⁴, N(R⁴)₂ or OR⁴, an alkylene group which can also form a cyclic ring with R⁷ or R⁹; R⁹ is separately in each occurrence hydrogen, a C₁₋₁₀ alkyl Y, —C(R⁹)₂—(CR⁹═CR⁹)_(c)—Y, or two or more of R⁹ can form a cyclic ring one or more of R⁹ or one or more of R⁹ can combine with Y to form a ring structure; and a is an integer of about 2 to about 6; b is separately in each occurrence an integer of about 0 to about 1; c is separately in each occurrence an integer of from about 1 to about 5; and d is separately in each occurrence an integer of about 2 to about
 4. 17. A polymerizable composition according to claim 15 comprising an aliphatic heterocyclic amine wherein the amine is a five or six membered heterocyclic compound.
 18. A polymerizable composition according to claim 15 wherein the amine is a conjugated imine.
 19. A polymerizable composition according to claim 15 wherein the amidine is a compound with an amidine structural component.
 20. A polymerizable composition according to claim 15 wherein the amine is an alicyclic compound having bound to the ring a substituent having an amine moiety wherein the alicyclic compound may have a second substituent which can contain one or more nitrogen, oxygen or sulfur atoms and/or one or two double bonds.
 21. A polymerizable composition according to claim 20 wherein the alicyclic ring is a 5 or 6 membered ring.
 22. A polymerizable composition according to claim 13 wherein the decomplexing agent is an acid.
 23. A polymerizable composition according to claim 13 which comprises a) from about 0.2 to about 8 to percent by weight of complex; b) from about 20 to about 95 percent by weight or less of monomers, oligomers or polymers; c) from about 10 to about 60 percent by weight of a thickener; and d) from about 5 to about 35 percent by weight of an elastomeric material. 